This invention relates to a method of providing ISDN switched access to a packet-based network, such as frame relay, offering PVC (Permanent Virtual Connection) services.
Frame relay is a technology for access to wide area networks. The frame relay protocol operates at a sublayer of the data link layer, which provides the minimum functionality needed to take advantage of the statistical properties of the communication. Unlike preexisting protocol suites in use in general topology subnetworks, it also performs relaying, and multiplexing at this sublayer. Other data link layer functions are provided only in systems connected to the edges of the frame relay subnetwork.
One of the requirements of telephone companies is to provide switched access to a frame relay network. Switched access allows calls to be set-up when needed allowing access by many callers. This brings the cost down to the user.
The prior art solution is to provide access using a dedicated PVC (Permanent Virtual Connection) in the Frame Relay network. The main shortcoming of this technique is that it provides access even when there is no traffic to send. This increases the cost of the access.